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Old October 14th 03, 01:51 AM
Brian Kelly
 
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Dick Carroll wrote in message ...

You raise an interesting question, Carl. How exactly should the
average ham go about proving that the RFI is indeed BPL, when the BPL
people say
"That's not us!'??



BPL has a unique "signature" (in the spectral/time domains) that can be
used to ID it.

Since there are different systems (SS from main.net and OFDM from Amperion,
for example) they have different signatures, which are distinct from other
sources
of interference and more traditional power line noise (of course the
utilities are
responsible for fixing the latter, too ... though their record is poor).



So to repeat, how does the average ham, whom you have exhorted to
"make sure it's BPL that you're complaining about", go about detecting
and sorting which is what, given that spectral analysis gear, and the
training to use it if it was available, is virtually nonexistnt in the
average hamshack? Is there a aural signature or more than one for the
different BPL modes? Is the Emmaus test site video/audio clip
reresentative enough to make the call, or is something more needed?


There's no mistaking the BPL signals in the Emmaus test area which are
SS although there's some discussion on that point. I didn't know what
to look for on my first pass through Emmaus and found all sorts of
crud particularly in the extensive commercial area. But I found a very
odd-sounding strong clicking noise in the area around the Emmaus High
School and reported it to Carl and Ed Hare who then told me the stuff
sounds like geiger-counter clicks. So I'd nailed it out of the chute
with just my little TS-50 HF mobile xcvr and a 2M magmaount whip. I've
probably heard every form of QRN/QRM out there by now and there is
*no* mistaking the BPL in use in Emmaus. The stuff grabs yer AGC and
it's all over.

The ARRL audio tracks and files don't do it justice, the spikes it
kicks out are too sharp and short to be captured properly with the
consumer-level digital recording/playback equipment used to generate
the recordings. OFDM is another form of the beast which I haven't
personally tuned on-site yet but the ARRL recordings ought to give you
the drift.


I expect that if it was indeed BPL RFI it would follow the power grid
pretty closely with signal strength highest when close, and tapering off
with distance away from the lines. But from the one report posted here
of a ham who said he heard it from a distance of 60 miles, seems like
propagation will play into the picture-to be expected at HF as all
experienced HF ham operators know. Or maybe *he* mis-identified it!

So who do hams call for assistance, the ARRL? I haven't seen anything
from them suggesting that.


Unfortunately the only help available is via the FCC and the ARRL is
beating the FCC into the ground over this one.

I seriously doubt the economics of BPL will ever bring it where I
live, even if it is approved, but others need to know.


w3rv